The Monofin: Your Weapon for a Killer Dolphin Kick

Want to improve and dominate your underwaters? Here’s how a monofin can help you power up your swimming.

It’s no secret that swimmers love to train with swim fins in the water. The benefits of using them are obvious: we are able to swim far faster than we ever would otherwise, our legs get a great power workout, and swimming at Mach-10 is simply a heap of fun.

You look in the swim bag of just about any competitive swimmer and you will see a pair of fins. Far less commonly, however, will you see it’s two-footed cousin…

The monofin.

The Benefits of Training with a Monofin

Misty Hyman was one of the original disrupters of the sport. The butterfly specialist had a unique style of “fish kicking”—dolphin kicking on her side off the start and walls—that hurled her past some of the best swimmers in the history of the sport.

She’d dip under the surface of the water and kick past the competition, kicking up to 35-40m underwater. (FINA eventually closed the loophole that allowed swimmers to kick underwater for longer than 15m in 1998.)

Hyman’s coach, Bob Gillett, who helped her develop her legendary underwater dolphin kick, credited Hyman’s underwater prowess to her fish kicks, and training with a Monofin.

Here’s how this piece of swim gear can give your underwaters a serious boost:

The monofin helps you “feel out” the full range of motion in the dolphin kick. This particular type of fin helps you experience the full whip of the dolphin kick. Its surface area has a way to forcing your core and lower back to engage in the kicking motion, which extends the range of the kick.

Power work for your dolphin kick. Using one of these bad boys will strengthen your core, lower back, and your legs.

Trains better motor patterns. Learning to swim fast means teaching your body how to move through the water at the speeds you want to swim at. Strapping on a Monofin will help you experience those upper tier speeds, and help train the motor patterns necessary (streamlining, bracing your core, snapping the full kick, etc) to get closer to those speeds without the fin on.

Improves undulation. Often you will see swimmers dolphin kick from their knees with a very rigid and limited undulation. The dolphin kick should originate from your upper body—not your knees. Training with a Monofin will deepen and enhance the undulation in her butterfly kick.

Helps build better rhythm. The first thing you notice when your fly kick gets better is that you can bang them out quickly and with almost rapid-fire precision. This kind of rhythm is built via repetition, but can be sped up by training the rhythm you want to hit when racing. By emphasizing the muscle groups that stabilize and drive the kick you are developing a stronger kicking rhythm.

Monofins: Where to Buy

Although the monofin is fully gangster when it comes to powering up your kick, there aren’t a lot of the mainstream swim brands that produce them.

One of my favorite swim gear companies, FINIS, has been producing them since the 1990’s, and actually made the monofin their very first offering.

The FINIS Foil Monofin

The FINIS Foil is the ideal choice for competitive swimmers looking to level up their dolphin kick. The rubber is the same that Zoomers are made of—if you’ve owned a pair you know they are basically indestructible—and the fin is long enough to give you a sense of the full range of your kicking motion.

They retail for around $50, will last you forever, and are available via Amazon.

About Olivier Poirier-Leroy

Olivier Poirier-Leroy is a former national level swimmer and the author of the books YourSwimBook and Conquer the Pool. He writes all things high-performance swimming, and his articles were read over 3 million times last year. His work has appeared on USA Swimming, SwimSwam, STACK, NBC Universal, and more. He's also kinda tall and can be found on Twitter.